The present invention concerns a device for attenuating the amplitudes of impacts, especially impacts against the wheel of a vehicle, with at least one piston that is accommodated in a housing and divides it into two attenuating spaces, that is attached to a piston rod, and that operates in conjunction with a hydraulically parallel component that handles smaller amplitudes.
Generally, the motion of the piston rod is attenuated rather weak for smaller amplitudes, allowing the extent of attenuation to be handled only by way of the impedances in the fluid-conveying channels.
European Patent A 0 848 182 describes a dashpot for vehicle wheels that operates in conjunction with a specific component in order to handle smaller amplitudes. The patent proposes a solution that involves an elastomeric component in the vicinity of the piston at the inner circumference and accommodating weaker wheel impacts. This attenuating component, preferably a ring, dynamically communicates with both an upper and a lower attenuating space by way of fluid-conveying channels. The two faces of the piston are demarcated by sliding valves. When the impacts are weak, hydraulic fluid can flow down toward the attenuating component and accordingly equilibrate smaller amplitudes essentially with no attenuation. The valves come into play conventionally when the flow is more powerful. There is a drawback to this approach. The piston must be precisely machined to accommodate the elastic elastomeric ring, and the incoming and outgoing fluid-conveying channels must be mechanically introduced subsequently.
The object of the present invention is to improve the prior art to the extent that the attenuation of vibrations with small amplitudes will be weak and will come into play only once the motions of the piston inside the cylinder are extensive. The piston itself will be conventional.
This object is attained by the characteristics recited in claim 1.
Advantageous and advanced embodiments will be evident from the subsidiary claims.
The object of the present invention accordingly features a space divided into subsidiary spaces by a diaphragm or by a solid sliding disc and hydraulically communicating parallel to the dashpot with the lower and/or upper attenuating space. The subsidiary spaces produced by the diaphragm or disc are designed to allow hydraulic fluid from their associated attenuating spaces to flow against them. It accordingly becomes possible for the subsidiary spaces demarcated by the diaphragm or disc to act outside the piston as equilibrating spaces with respect to slight motions thereof. The particular equilibrating space, or demarcated subsidiary space, can be charged with hydraulic fluid from the top or bottom through apertures similar to those in a sieve for example with essentially no attenuation taking place until the diaphragm or disc comes to rest against one of the two opposing and preferably curved walls of its associated subsidiary space. This measure results in a relatively unattenuated motion in the vicinity of smaller amplitudes. Not until these short routes have been exhausted will the actual attenuation typical of the prior art, specifically by way of the known sliding valves, come into play.
Behavior during the transition to hard attenuation can be controlled by varying the geometry of the particular subsidiary space and its components and their intakes, the rigidity of the diaphragm, and the position of the apertures for instance, and the transition will be smoother.